Here is a passage that should be self-explanatory. More info later…
To the pure, all things are pure; but to those who are defiled and unbelieving, nothing is pure; but both their mind and their conscience are defiled.
To the pure, all things are pure, but to those who are corrupted and do not believe, nothing is pure. In fact, both their minds and consciences are corrupted.
Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled.